Disclosed herein is a method for method and apparatus for feeding media sheets in an image production device, as well as corresponding apparatus and computer-readable medium.
In image production devices where sheets are fed from a media stack, it is important to attain consistent separation of the top media sheet from the rest of the media stack, especially media sheets of larger length. This is especially important in vacuum corrugation feeding due to the lower acquisition forces available.
If the top media sheet is not fully separated due to edge welds (sheets sticking together at the edges from the shearing operation at the mill), or other contact issues caused by ambient conditions and interactions with the paper coatings, the feed head may not acquire the sheet properly and this may lead to several failure conditions. These issues generally result in multi-feeds, such as when 2 or more media sheets are acquired and fed as a single media sheet, or mis-feeds, such as when a media sheet is not acquired within the necessary time to match the system pitch timing.
In an attempt to separate the top media sheets at the leading edge of the media stack conventional image production devices use “fluffers” to force air into the media stack. The theory of fluffing up the lead edge of the stack is based on the idea that when the top media sheet is being acquired by the feed head the resistance at the lead edge of the media sheet can be reduced by forcing air into the lead edge of the media stack.
However, the air being forced into the media stack cannot be directed accurately enough to always separate the top media sheet. The fluffer forces air to a subset of media sheets at the top of the media stack and does not always focus on the separation of the top media sheet.
SUMMARY
A method and apparatus for feeding media sheets in an image production device is disclosed. The method may include applying a downward airflow to a top of a leading edge of a media sheet located at a top of a media stack that is to be fed to an image production section of the image production device, and applying a vacuum airflow to the top of the leading edge of the media sheet located at the top of the media stack that is to be fed to the image production section of the image production device, the applied downward airflow and the applied vacuum airflow causing the top media sheet to separate from the media stack and be acquired to the feed head for feeding the separated top media sheet to the image production section.